In time-division multiple access (TDMA) packet-switched communication systems, a base site transmits data to many different subscriber units using a common frequency channel by dividing the data into units called packets. Each packet may be divided to form segments. A segment contains the amount of data which may be transmitted during a discrete time slot of T seconds within a frame. A frame consists of n of these time slots, where n is a positive integer. Thus, a base site can communicate with multiple subscriber units on a basis of non-overlapping transmission bursts using a same carrier frequency.
In some of these TDMA packet-switched communication systems, subscriber units are characterized by the number of time slots per frame on which the subscriber unit hardware is capable of transmitting and receiving data. These characterizations may be divided into two basic categories: single slot subscriber units and multiple slot subscriber units. Single slot subscriber units are physically capable of transmitting and receiving data on one of the n time slots per frame. Multiple slot subscriber units are physically capable of transmitting and receiving data on as many as n time slots per frame. In systems supporting both types of subscriber units with one air interface protocol, there is a need for an efficient method of utilizing the downlink channel (from the base site to the subscriber unit) such that the higher throughput capability of the multiple slot subscriber units is exploited without degrading the performance of the single slot subscriber units.